Name Meaning: Drawn Out Face
Geologic Era: Late Carboniferous to Early Permian
Estimated Range: USA
Location Found: Texas
Size: 2 meters long (average); 3 meter length also reported
Extinction Date: 295 million years ago
Eryops’ contribution to the museum is a tooth, and as one can see from the skeletal restoration, Eryops had plenty of them. In a reversal of what is usually the case for fossil preservation, the best known part of Eryops’ anatomy is its skull, since it is unusually heavily built. To me, Eryops resembles a cross between an alligator and a salamander, and it may have shared the behavioral traits of both.
The mouth of Eryops has a design well suited to catching and holding onto slippery prey such as fish and other amphibians. A large number of teeth would be more able to hold on to a wriggling prey item than fewer, larger teeth would be. Due to its size, Eryops would have likely been the top predator in its environment. Its only theoretical competition in terms of size would have been larger synapsid animals such as Dimetrodon, though the two probably inhabited different environments and did not directly compete for food.
Eryops was not a particularly fast animal, and would have moved somewhat awkwardly on land. In contrast to this, its ear structure suggests that Eryops heard best on land. This paints a picture of an animal that probably spent much of its time near water, probably near lakes and rivers. While it may have lived in or near water, Eryops was not a good swimmer, having a very stiff, immobile tail. A more likely scenario would be sitting in ambush in shallow water (similar to modern alligators and crocodiles).
One thing Eryops could not do is chew its food. This meant that any prey taken had to be swallowed whole. Eryops did have an adaptation to deal with this: a series of tooth-like projections in the back of its palate (roof of mouth) that would have further assisted in pulling prey back toward the digestive tract. A similar adaptation is seen in mosasaurs and modern moray eels, which have structures called pharyngeal jaws in the throat, which performs much the same function and the projections in Eryops’ palate. Swallowing prey whole does have its risks, including prey still being alive when it reaches the digestive tract or prey becoming lodged in the esophagus. Eryops could possibly have torn pieces from larger prey to swallow, but its body structure would have made even this simple seeming action difficult.
Full Skeleton: By Daderot – Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=8710123
Life Restoration: http://spinops.blogspot.com/2012/01/eryops-megacephalus_24.html